The Public Switch Telecommunication Network (PSTN) was built without anticipating the threats that we face today, from malicious users to foreign governments and terrorist groups who aim in compromising or disrupting the national telecommunications infrastructure at the appropriate time. The Common Channel Signaling System 7 is a set of protocols that are used in the PSTN to setup and tear down communications between subscribers. The SS7 was developed without security objectives in mind (i.e. confidentiality, integrity, availability) that can help protect against attacks that can be realized today. Packet based networks, such as the Internet, are known to have vulnerabilities due to lack of security objectives as well. The difference is that the Internet is accessible by anyone who has connectivity through an Internet Service Provider. With the PSTN, however, access to the core network is restricted to the carriers or service providers who are typically commercial organizations with financial objectives in mind, rather than the objective of generating attacks against subscribers or networks. As such, the convergence between circuit switch (SS7) and packet based (i.e. Internet) networks raises several concerns. An attack against a Signaling Gateway, the demarcation point between IP and SS7 based networks, can cause unexpected conditions to occur. Thus, the risk of an attacker sending specially crafted messages from an IP network to an SS7 network increases. Accordingly, a need currently exists for systems and methods for detecting security vulnerabilities in networks that use voice over IP communications. Such need also exists for NGN (Next Generation Networks) and IMS (IP Multimedia Subsystem).